1. Field of the Invention
The present invention relates to a construction machine including winches.
2. Description of the Related Art
A crawler crane that is a kind of mobile crane will be explained. FIG. 7 shows a lattice boom crawler crane xe2x80x9chereinafter, can be referred to as LBCCxe2x80x9d and FIG. 8 shows a telescoping boom crawler crane xe2x80x9chereinafter, an be referred to as TBCCxe2x80x9d. Numeral 1 is a crawler type of a lower traveling body. An upper rotating body 3 is mounted on the lower traveling body 1 via a rotation bearing 2 rotatably around a longitudinal axis. In the upper rotating body 3, a lattice boom 4 is provided in FIG. 7, and a telescoping boom 5 is provided in FIG. 8, to freely raise and lower, respectively.
As a means for making the booms 4, 5 raise and lower, a boom up-and-down rope 6 and a first winch 7 for winding and rewinding the rope 6 are provided in LBCC, and a boom up-and-down cylinder 8 is provided in TBCC.
As lifting means for a lifting work, a second xe2x80x9cmainxe2x80x9d winch 9 and a third xe2x80x9cauxiliaryxe2x80x9d winch 10 are provided in the upper rotating body 3 of LBCC and a first xe2x80x9cmainxe2x80x9d winch 11 and a second xe2x80x9cauxiliaryxe2x80x9d winch 12 are provided in the upper rotating body 3 of TBCC. A main hook 14 is suspended to rise and fall by means of a main rope 13 taken from the main winches 9, 11, and a sub hook 16 is suspended to rise and fall by means of a auxiliary rope 15 taken from the auxiliary winches 10, 12.
In such mobile cranes, in order to improve work efficiency at a small space, it is preferable that a radius R of a rotating rear end is as small as possible.
In FIGS. 7 and 8, a plurality of winches is arranged horizontally by side by side in the upper rotating body 3 in order to facilitate the winding and rewinding of the ropes winded on the winches. Therefore, a horizontal space that the winches occupy increases.
Also, because the rope-winding capacity of winch increases as the lifting ability is set to be great, the horizontal space that the winches occupy further increases.
Therefore, arranging efficiency of the whole space in the upper rotating body is deteriorated, and it was difficult to secure a space for arranging other machinery xe2x80x9cengine, hydraulic equipment, operation oil tank, fuel tank and the likexe2x80x9d. Also, in order to secure the space, a radius R of the rotating rear end increased.
Particularly, in TBCC of FIG. 8, in addition to the need for improving the lifting ability in a limited space xe2x80x9cto set a great lifting ability at a small work radiusxe2x80x9d, so as to reduce the overhanging amount of the boom 5 in transit, an up-and down swinging axis is arranged rearward of the center of rotation of the rotating body 3. Also, because the mounting point of the boom up-and-down cylinder 8 is positioned at the vicinity of the center of rotation of the rotating body, the space for arranging the winches cannot be secured at the center part of rotation. As a result, the winches 11, 12 must be arranged at the rear part of the rotating body. Because the space that the winches occupy is great horizontally at the rear part of the rotating body, the radius R of the rotating rear end becomes greater.
An object of the present invention is to provide a construction machine in which a space that winches occupy can be reduced without decrease of workability, so that a space of an upper rotating body can be utilized effectively. Particularly, the object of the present invention is to provide a construction machine in which a space for arranging other equipment can be easily secured in a mobile crane of which the whole size is limited.
The construction machine of the present invention has the following constitution.
The construction machine comprises a lower traveling body, an upper rotating body which is mounted rotatably on said lower traveling body, and winches provided at rear part of said upper rotating body, wherein at least two of said winches are arranged to be overlapped vertically with each other.
In this case, because at least two of said winches are arranged to be overlapped vertically with each other, a horizontal space that the winches occupy can be reduced to secure a space for arranging other equipment. Therefore, because a limited space of the upper rotating body can be utilized effectively in a mobile crane of which the whole size is limited, the layout of other equipment can be facilitated.
Because the space that the winches occupy can be reduced at the rear part of the upper rotating body, the radius R of the rotating rear end xe2x80x9cdistance from center of rotation to rear end of the upper rotating bodyxe2x80x9d can be reduced.
Also, because the center of gravity of the construction machine can be deviated backward, the workability can be improved. That is, the lifting ability in the crane and the attachment supporting ability in earth-moving machine can be increased.